These rounds are the same caliber as about half of the 66,000 rounds found in a woman's car by Border Patrol agents a few weeks ago. That woman was stopped Papago Farms, on the Tohono O'odham Nation, and was also carrying six firearms with her, according to records.

As for Enriquez, the federal complaint against him says didn't declare the ammunition, and later told officers he knew it was illegal to transport ammo to Mexico without a license to export it.

Enriquez told officers that he picked up the ammo from a warehouse on the Arizona side of the border, and was going to deliver it to "unknown individuals" in Mexico, the complaint states.

A detention hearing for Enriquez hasn't yet been held, according to federal court filings.